Although cotton fabric possesses advantages of good elasticity, good moisture absorbability, breathability and comfort, they wrinkle easily during wearing and after laundering due to the breakage and deformation of the hydrogen bonds in the non-crystalline regions of the cellulose fibers by external forces or by the action of moisture, under which hydrogen bonds are once again formed. Especially after repeated laundering, there is a fuzzy appearance and a general fading of the clothes.
There have been many attempts to improve the quality of cotton fabrics. For example, prior art method involves the modification of the surface of cotton fabrics with either polymeric resins to resist wrinkling, or alternately with enzymes to obtain washing-resistance. However, there are no methods in the prior art that teach the use of a resin treatment agent in combination with an enzymatic treatment to improve the quality of cotton fabrics.
Ironing-free treatment includes selecting a suitable polymeric resin, applying the polymeric resin to the clothes, followed by drying and baking, to make the polymeric resin form stable chemical cross-linking between chains of the cellulose macromolecules and thereby improve the properties of deformation resistance and deformation restoration. Consequently, elasticity is increased and wrinkling is reduced.
One purpose of an enzyme treatment is to improve the quality of the finished goods by dehairing and smoothing. The enzymes commonly used for improving washing-resistance are hydrolases, such as cellulases and pectases, which hydrolyze exposed beta-1,4 bonds in cellulose and decompose the cellulose molecules to low molecular hydrolysates, such as cellobiose and glucose. This leads to removal of the fibrils, which are the most exposed part of the fabric. The removal of fibrils is believed to directly improve the softness of the garments and also to lead to better color and cleanliness, both by removing soil attached to the fibrils and by improving the penetration of other cleaning compounds being used. The removal of fibrils initially also helps to prevent a subsequent formation of fibrils. At the same time, results in strength loss of the cotton fabric to make fuzz and loose surface fibers, which re-occurred after wearing and washing, easily broken and removed. After repeated experiments, washing-resistance is improved by a single enzymatic treatment. However, after the enzymatic-treated fabric has been washed several times, the appearance of the washed fabric merits a rating of 2.0 to 3.0 on the ASTM scale, but cannot reach the desired rating of 4.0 according to ASTM testing method. When the cotton fabric is subjected to the enzymatic treatment several times, it results in weight loss of the cotton, serious strength loss of fabric and less improvement on washing-resistance. Besides, not only does this result in increased costs, the operations are also complicated due to the demanding requirements of the enzymatic treatment.
Traditional washing-resistant treatments for cotton fabrics include methods for polymeric resin treatment of cotton fabrics comprising the steps of, knitting, scouring, dyeing, soaping, fixing, softening, dehydrating, drying, heat-setting, making garments, applying a polymeric resin finish to the garments, tumble drying and testing. The traditional washing-resistant treatment includes methods for enzymatic treatment of cotton fabrics comprising the steps of knitting, scouring, dyeing, soaping, fixing, softening, dehydrating, drying, heat-setting, making garments, treating the garments with enzymes, tumble drying and testing.
Numerous tests have proved that either one of the above two methods, when used separately, are unable to achieve the good properties of both wrinkle-resistance and washing-resistance. In addition, as the two methods are operated on ready-to-be-worn clothes, the operation is complicated, less efficient and expensive.
Therefore there is a need to improve the existing methods in the art, which currently employ either a polymeric resin treatment agent or an enzymatic treatment.